I am using visual studio 2010. I have a text box bound to a sql datetime field.I have to be able to either set or clear the text box. I can set it to any date fine, but when I try to clear it I am unable to save the record.i am using the binding navigator to save.
Im writing an app which connects to a SQL Server database, via datasources / datatable.When Im looking at my .xsd I can see DataTables containing DataColumns. Each DataColumn has a 'NullValue' property which defaults to '(Throw exception)'.Because I have nulls in my tables I have gone through the fields and set all System.String fields to NullValue = 'Empty', System.int32 field to NullValue = 0.
i'm not 100% sure about sql server but i think it doesn't accept null value for date type columns but in oracle, a date column can accept a null value. and since i'm using oracle, this is causing some problems because in my form, a textbox item bound to a date column will not accept a null value. reading thru some threads, it would seem that it is not possible to pass a null value to a date type in .Net.
I have the following If Trim(txtConfirmationDate.Text) <> "" Then sqlinsert2.Parameters.AddWithValue("@CONFIRMDATE", CDate(txtConfirmationDate.Text)) Else sqlinsert2.Parameters.AddWithValue("@CONFIRMDATE", VB.vbNull) End If Unfortunately, it writes "01/01/1900" to the database. How do I get it to just leave the field as NULL?
I am building a data based application using VB 2008 an SQL Express. I need to create textboxes on my form using code, (With & End With) method. I need a simple code string that will allow the app to check if the field to wich the textbox wil be databound is Nul, If so the textbox will not be created.
I'm fairly new to ASP.NET & VB.I've been asked to take an existing textbox that is automatically filled with the current date and allow the user to either add a "+" or "-" and a number or a spcific number and convert that into a date.I underdstand the basic concept on how to do this, but I'm running into some problems using the proper commands in order for this to work.The Textbox is called txtDate.What I've tried to do is this:
If txtDate = '+' Or '-' Then DateAdd("d", txtDate, today) End If
Here is what the whole thing looks like:
Protected Sub DateEnter_Click(ByVal sender As[code].....
how to delete row in a CSV file where there is a null value in a partcular column? I am using VB. There are three columns I am using Post Date, Account Number, and Credit Amount. I want to delete all rows with null values in the Account Number column. I am very new to VB, took one class. I am using the Microsoft.VisualBasic.FileIO.TextFieldParser?
Question is: How to test for null value of a field in an ADO recordset.Using Visual Studio 2010 Ultimate - VB.NET
ADO Connection to ODBC database
I am working with a table that contains about 10,000 records of which I need to do additional processing on about 1500. The records I need to process are qualified by the field'Cataloged' = True. The problem I have is the table allows for True, False or Null values (I have no direct control of the table to change from allowing Null) for the field I need to test.I run into errors when the value of the field is Null and need to figure out how to determine its Null state prior to trying to qualify the field as True or False value to prevent the errors.
I'm trying to test a varbinary(max) field to see if it's null. I'm trying to figure out if it's a null or not in the select statement, hoping to avoid having to do this locally for every row of the returned dataset. This is the SQL I'm using,
I am trying to do a SQL query to see if an Address already exists in my database. My addresses are structure like this:
line1 line2 line3 city state zipcode country
Sometimes line2 and line3 are NULL values in my database.I am using .NET TableAdapter and DataTable to make my query. When I try to pass in my line2 parameter (@line2) it is equal to a string with value = nothing. My database does not interpret this as NULL and says the records don't match, but I know they do? How do I pass in a string = nothing and have it compare to a NULL value in the database as being equal? I have tried string = DBNULL.value but won't compile.I have done similar comparisons with integers etc. using integer = Nullable (of integer) but this does not exist for strings.
I've got a table that caches calculated values for certain dates. I want to use LINQ to select all rows where the calculated value fields are null.But when I use isNothing I get an error that LINQ can't translate this into T-SQL. Is there a way to select null values with link, like this...?
Dim var = From rec As Record In myDataContext.Records Where IsNothing(rec.calculatedValue) Select rec
Other posts on stackoverflow mostly discuss how to avoid or check for null values with LINQ.
Note: I can't just set cacluatedValue's default to -1 to flag records whose calculated value has not been set (and then select those records) because I run queries that sum/average the calculated values. Selecting nulls seems cleaner and less bug-prone.
I have the following query that I use to create a new record in a database. If I leave any field on the form blank, for example, it throws the error "Memo.Lastname" cannot be a zero length string. Other than that the query executes appropriately. Private Sub cmdSaveMemo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSaveMemo.Click If Len(Me.txtMemoID.Text) <> 0 Then Memo.SaveMemo [Code] .....
I have a date time picker bould to a Nullable Datetime field in a sql server datatable. The ShowCheckBox option is set to true. If the user unchecks the checkbox on the datetimepicker I would like to the field to be set back to null in the DataTable. The default behaveour does not seem to do this and there is no specific event for the uncheck.
Private Sub dtpCertDate_ValueChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles dtpCertDate.ValueChanged If dtpCertDate.Focused Then
I have a couple of textfields in a Windows form. One of these textfields is allowed to be NULL. When I enter a value for every field, it is all inserted, no problem. When I leave the field (txtGewicht) blank, I can't seem to be able to insert NULL in Access Database.
If Double.TryParse(txtGewicht.Text, 0) Then klant.Gewicht = Double.Parse(txtGewicht.Text) Else
This is what I get:
"Cannot set column 'Gewicht' to NULL, please use DBNull instead"
So I changed 'Nothing' to DBNull.value, but it then tells me that System.DBNull cannot be converted to type Double.
I'm making a data application and using the data adapters, I created a query in the designer: EmpActivities_TableAdapter.InsertQuery(IdTextBox.Text, ActivityComboBox.Text, DescriptionTextBox.Text, Cdate(adddate.text)) The question is how can I set the adddate to null or nothing and save it? I'm using SQL server for the data.
How can i remove this in my crystal report . this value is showing if my date field in null . "1/1/1900 12:00:00 AM". I don't want to show thin is my report.I have two dates , case open date and case close date . if the case is not closed its showing this value so i want to remove this.I am using sqlsever.
I am working with calendar inside GridView using VB. I have some NULL date on the DDBB. I can fix the problem using EVAL, but when I try to save the date from the calendar, I got an error telling me that their is no @variable declared.[code]Everything is fine but I got: Must declare the scalar variable "@tDate" trying to save.This is beacuse I'm not using Bind, but with BIND I cannot run checkDate.
i have a datetimepicker with showcheckbox properties set to true..
when there is date in database, the checkbox is checked..
but when the database is null, the checkbox is unchecked..
here's the code:
Sub checkeddate() 'to set DateTimePicker.check (compare from database) 'if db is not null, then CheckBox is checked If IsDBNull(DataSet.Tables("AssetMaster").Rows.Item(curPosition).Item(19)) = False Then